triqs.gfs.gf.Gf.fit_tail

Gf.fit_tail(*args, **kw)

Dispatched C++ function(s).

[1] (g: Gf[MeshImFreq, 2],
     known_moments: ndarray[complex, 3] = [])
  -> tuple[ndarray[complex, 3], float]

[2] (g: Gf[MeshImFreq, 0],
     known_moments: ndarray[complex, 1] = [])
  -> tuple[ndarray[complex, 1], float]

[3] (g: Gf[MeshReFreq, 2],
     known_moments: ndarray[complex, 3] = [])
  -> tuple[ndarray[complex, 3], float]

[4] (g: Gf[MeshReFreq, 0],
     known_moments: ndarray[complex, 1] = [])
  -> tuple[ndarray[complex, 1], float]

[5] (bg: BlockGf[MeshImFreq, 2],
     known_moments: [ndarray[complex, 3]] = <unprintable>)
  -> tuple[[ndarray[complex, 3]], float]

[6] (bg: BlockGf[MeshImFreq, 0],
     known_moments: [ndarray[complex, 1]] = <unprintable>)
  -> tuple[[ndarray[complex, 1]], float]

[7] (bg: BlockGf[MeshReFreq, 2],
     known_moments: [ndarray[complex, 3]] = <unprintable>)
  -> tuple[[ndarray[complex, 3]], float]

[8] (bg: BlockGf[MeshReFreq, 0],
     known_moments: [ndarray[complex, 1]] = <unprintable>)
  -> tuple[[ndarray[complex, 1]], float]

[1, 2, 3, 4] Fit the high-frequency tail of a Green’s function using a least-squares procedure.

The result is the set of expansion moments that best reproduces the high-frequency behavior of \(G\) on the configured tail-fit window. Known moments, when provided, are treated as exact constraints on the fit.

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[5, 6, 7, 8] Fit the high-frequency tail of a block Green’s function using a least-squares procedure.

Each block is fitted independently using fit_tail. The returned error is the maximum across blocks.

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Parameters:

gGf[MeshImFreq, 2], Gf[MeshImFreq, 0], Gf[MeshReFreq, 2], Gf[MeshReFreq, 0]

The Green’s function whose tail is to be fitted.

known_momentsndarray[complex, 3], ndarray[complex, 1]

Array of known high-frequency moments to constrain the fit.

bgBlockGf[MeshImFreq, 2], BlockGf[MeshImFreq, 0], BlockGf[MeshReFreq, 2], BlockGf[MeshReFreq, 0]

The block Green’s function whose tail is to be fitted.

Returns:

[1, 3]tuple[ndarray[complex, 3], float]

A pair containing the fitted tail moments and the fitting error.

[2, 4]tuple[ndarray[complex, 1], float]

A pair containing the fitted tail moments and the fitting error.

[5, 7]tuple[[ndarray[complex, 3]], float]

A pair containing the per-block fitted tail moments and the worst-block fitting error.

[6, 8]tuple[[ndarray[complex, 1]], float]

A pair containing the per-block fitted tail moments and the worst-block fitting error.